The new virus is a coronavirus, named for its halo or crown-like (corona) appearance when viewed under a microscope.Image courtesy CDC/Dr. Fred Murphy.

Scientists have discovered a new virus in people that belongs to the same family of viruses as the virus that causes SARS. Called coronaviruses for their crown-like appearance, viruses in this family may be surprisingly widespread and may cause a variety of respiratory diseases.

Dutch researchers found the virus in a seven-month old baby admitted to an Amsterdam hospital in January 2003 for shortness of breath, fever, and swollen eyes. She was successfully treated with drugs that cleared her lungs and nose.

They were surprised to discover that the virus did not match any known wintertime viruses such as influenza or rhinovirus. They collected the virus from mucus in the baby’s nose.

Using a new technique they pioneered, Ben Berkhout of the University of Amsterdam and colleagues sequenced snippets of DNA from the virus, compared it to known viruses, and discovered it is a new coronavirus.

They also sequenced its complete genome and compared it to other coronaviruses such as SARS. The symptoms the new virus causes are much less severe than SARS, even though the two viruses share some genomic similarities.

Until last year when scientists identified the SARS virus, only two coronaviruses, which cause the common cold, had been discovered since the 1960s. This is the fourth known coronavirus, and the new research could help extend understanding of this family of viruses.

The baby’s illness was not an isolated case. In further tests done retrospectively, seven other patients admitted to the hospital for respiratory problems in 2003 had carried the same virus, and it reappeared this past January.

The researchers say there is no reason to believe the virus is restricted to Amsterdam. Berkhout led the study.

The new sequencing technique is called Virus-Discovery-cDNA-AFLP. It can be used to identify different types of unknown viruses, which could be a boon for doctors and scientists trying to pinpoint emerging infections.

Van der Hoek, Lia, et al. Identification of a new human coronavirus. Published online in Nature Medicine March 21, 2004.